Multivalent pneumococcal polysaccharide-protein conjugate composition

ABSTRACT

Provided are mixed carrier, multivalent pneumococcal conjugate compositions comprising 16 different pneumococcal capsular polysaccharide-protein conjugates, wherein each of the conjugates includes a capsular polysaccharide from a different serotype of  Streptococcus pneumoniae  conjugated to either tetanus toxoid or CRM 197 , wherein the  Streptococcus pneumoniae  serotypes are selected from 1, 3, 4, 5, 6A, 6B, 7F, 9V, 12F, 14, 18C, 19A, 19F, 22F, 23F, and 33F, wherein two of the capsular polysaccharides are conjugated to tetanus toxoid and the remaining capsular polysaccharides are conjugated to CRM 197 , and wherein the two capsular polysaccharides that are conjugated to tetanus toxoid are selected from the group consisting of serotypes 1, 3, and 5. Also provided are methods of producing the mixed carrier, multivalent pneumococcal conjugate compositions and methods of using the same for prophylaxis against  Streptococcus pneumoniae  infection or disease in a subject.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a U.S. National Stage application of PCT/US2017/045479 filed 4 Aug. 2017, which claims the benefit of, and relies on the filing date of, U.S. provisional patent application No. 62/371,529, filed 5 Aug. 2016, the entire disclosure of which is herein incorporated by reference.

TECHNICAL FIELD

This application relates generally to mixed carrier, multivalent pneumococcal conjugate compositions, vaccines comprising the same and methods of using these compositions and vaccines for prophylaxis of Streptococcus pneumoniae infection or disease in a subject.

BACKGROUND

Pneumococcus (Streptococcus pneumoniae) is a Gram-positive, lancet-shaped, facultative anaerobic bacteria with over 90 known serotypes Most S. pneumoniae serotypes have been shown to cause disease, with the 23 most common serotypes accounting for approximately 90% of invasive disease worldwide. Serotypes are classified based on the serological response of the capsular polysaccharides, the most important virulence factor for pneumococcus. Capsular polysaccharides are T-cell independent antigens that induce antibody production in the absence of T helper cells. T-cell independent antigens generally induce antibodies with low affinity and short-lived immune responses with little to no immunological memory.

Initial pneumococcal vaccines included combinations of capsular polysaccharides from different serotypes. These vaccines can confer immunity against S. pneumoniae in patients with developed or healthy immune systems, however, they were not effective in infants, who lack a developed immune system, and elderly subjects, who often have impaired immune function. To improve the immune response to pneumococcal vaccines, particularly in infants and elderly subjects, who are at higher risk to develop S. pneumoniae infection, capsular polysaccharides were conjugated to suitable carrier proteins to create pneumococcal conjugate vaccines. Conjugation to a suitable carrier protein changes the capsular polysaccharide from a T-cell independent antigen to a T-cell dependent antigen. As such, the immune response against the conjugated capsular polysaccharide involves T helper cells, which help induce a more potent and rapid immune response upon re-exposure to the capsular polysaccharide.

There are at least two approaches to developing pneumococcal conjugate vaccines: the single carrier approach and the mixed carrier approach. The immunogenicity of different capsular polysaccharide conjugates may vary depending on the pneumococcal serotype and carrier protein used. In the single carrier approach, the capsular polysaccharides from different serotypes are conjugated to a single protein carrier. Pfizer's PREVNAR series of vaccines is an example of a single carrier approach where the different capsular polysaccharides are conjugated to the CRM₁₉₇ protein carrier, a non-toxic variant of the diphtheria toxoid having a single amino acid substitution of glutamic acid for glycine. The 7-valent PREVNAR vaccine (PREVNAR) was first approved in 2000 and contains the capsular polysaccharides from the seven most prevalent serotypes: 4, 6B, 9V, 14, 18C, 19F and 23F. The 13-valent vaccine, PREVNAR 13, added the serotypes 1, 5, 7F, 3, 6A, and 19A to the CRM₁₉₇ protein carrier. The protein carrier, CRM₁₉₇, used in the single carrier, PREVNAR vaccines has never been used as part of a mixed carrier system in a pneumococcal conjugate vaccine.

The second pneumococcal vaccine approach is the mixed carrier approach. In the mixed carrier approach, instead of using a single protein carrier, two or more protein carriers are used, with capsular polysaccharides from specific serotypes conjugated to a first protein carrier and capsular polysaccharides from different serotypes conjugated to at least a second, different protein carrier. For example, GlaxoSmithKline has developed SYNFLORIX, a 10-valent (serotypes 1, 4, 5, 6B, 7F, 9V, 14, 18C, 19F and 23F), mixed carrier, pneumococcal conjugate vaccine that uses H. influenzae protein D, tetanus toxoid, and diphtheria toxoid as the protein carriers. In SYNFLORIX, serotypes 1, 4, 5, 6B, 7F, 9V, 14, and 23F are conjugated to protein D; serotype 18C is conjugated to tetanus toxoid; and serotype 19F is conjugated to diphtheria toxoid [7]. Serotype 3 was removed from the 11-valent precursor to SYNFLORIX because it did not show serotype-specific efficacy in an acute otitis media trial [1]. Another group, Aventis Pasteur, developed an 11-valent (serotypes 1, 3, 4, 5, 6B, 7F, 9V, 14, 18C, 19F, and 23F), mixed carrier, pneumococcal conjugate vaccine using diphtheria toxoid and tetanus toxoid as protein carriers [2, 3]. Capsular polysaccharides from serotypes 3, 9V, 14, and 18C can evoke a better response when conjugated to diphtheria toxoid than they do when conjugated to tetanus toxoid [2, 6]. Thus, serotypes 3, 6B, 14, and 18C were conjugated to diphtheria toxin and serotypes 1, 4, 5, 7F, 9V, 19F, and 23F were conjugated to tetanus toxoid. The development of this mixed carrier, pneumococcal vaccine was terminated due, in part, to technical reasons and the potential of a reduced response when combined with acellular pertussis vaccines [3]. Recently, serotype 5 as well as 1 was reported as having one of the lowest observed OPA titres from all PREVNAR 13 serotypes, in which there was an associated correlation between IgG titer and OPA activity [4]. Also it was suggested that for serotype 3, a much higher serum IgG concentration would be needed for protection [5].

SUMMARY

This application provides new and improved mixed carrier, multivalent pneumococcal conjugate compositions and vaccines comprising the same. In one aspect, this application provides a mixed carrier, multivalent pneumococcal conjugate composition, comprising 16 different pneumococcal capsular polysaccharide-protein conjugates, wherein each pneumococcal capsular polysaccharide-protein conjugate comprises a protein carrier conjugated to a capsular polysaccharide from a different serotype of Streptococcus pneumoniae, wherein the Streptococcus pneumoniae serotypes are selected from 1, 3, 4, 5, 6A, 6B, 7F, 9V, 12F, 14, 18C, 19A, 19F, 22F, 23F, and 33F, wherein the protein carrier is CRM₁₉₇ or tetanus toxoid, wherein two of the capsular polysaccharides are conjugated to tetanus toxoid and the remaining capsular polysaccharides are conjugated to CRM₁₉₇, and wherein the two capsular polysaccharides that are conjugated to tetanus toxoid are selected from the group consisting of serotypes 1, 3, and 5.

In some embodiments, the capsular polysaccharides from serotypes 1 and 5 are conjugated to tetanus toxoid, and the capsular polysaccharides from serotypes 3, 4, 6A, 6B, 7F, 9V, 12F, 14, 18C, 19A, 19F, 22F, 23F, and 33F are conjugated to CRM₁₉₇.

In another embodiment, the capsular polysaccharides from serotypes 1 and 3 are conjugated to tetanus toxoid, and the capsular polysaccharides from serotypes 4, 5, 6A, 6B, 7F, 9V, 12F, 14, 18C, 19A, 19F, 22F, 23F, and 33F are conjugated to CRM₁₉₇.

In yet another embodiment, the capsular polysaccharides from serotypes 3 and 5 are conjugated to tetanus toxoid, and the capsular polysaccharides from serotypes 1, 4, 6A, 6B, 7F, 9V, 12F, 14, 18C, 19A, 19F, 22F, 23F, and 33F are conjugated to CRM₁₉₇.

In some embodiments, the mixed carrier, multivalent pneumococcal conjugate composition further comprises an adjuvant, such as an aluminum-based adjuvant, including, but not limited to aluminum phosphate, aluminum sulfate, and aluminum hydroxide.

Another aspect is directed to the use of the mixed carrier, 16-valent pneumococcal conjugate composition as a vaccine.

Yet another aspect is directed to a vaccine comprising the mixed carrier, 16-valent pneumococcal conjugate composition and a pharmaceutically acceptable excipient.

Yet another aspect is directed to a method for prophylaxis of Streptococcus pneumoniae infection or disease in a subject, such as a human, the method comprising administering a prophylactically effective amount of the mixed carrier, 16-valent pneumococcal conjugate compositions or a vaccine comprising the same to the subject.

In certain embodiments, the subject is a human who is at least 50 years old and the disease is pneumonia or invasive pneumococcal disease (IPD).

In other embodiments, the subject is a human who is at least 6 weeks old and the disease is pneumonia, invasive pneumococcal disease (IPD), or acute otitis media (AOM). In some embodiments, the human subject is 6 weeks to 5 years of age. In other embodiments, the human subject is 2 to 15 months of age or 6 to 17 years of age.

In certain embodiments, the mixed carrier, 16-valent pneumococcal conjugate composition or vaccine is administered by intramuscular injection. In certain embodiments, the mixed carrier, 16-valent pneumococcal conjugate composition or vaccine is administered as part of an immunization series.

The foregoing and other objects, features, and advantages of the mixed carrier, 16-valent pneumococcal conjugate compositions will become more apparent from the following detailed description.

Definitions

In order for the present disclosure to be more readily understood, certain terms are first defined below. Additional definitions for the following terms and other terms may be set forth through the specification.

As used in this specification and the appended claims, the singular forms “a,” “an,” and “the” include plural references unless the context clearly dictates otherwise. Thus for example, a reference to “a method” includes one or more methods, and/or steps of the type described herein and/or which will become apparent to those persons skilled in the art upon reading this disclosure and so forth.

Adjuvant: As used herein, an “adjuvant” refers to a substance or vehicle that non-specifically enhances the immune response to an antigen.

Administer: As used herein, “administering” a composition to a subject means to give, apply or bring the composition into contact with the subject. Administration can be accomplished by any of a number of routes, such as, for example, topical, oral, subcutaneous, intramuscular, intraperitoneal, intravenous, intrathecal and intradermal.

Approximately: As used herein, the term “approximately” or “about,” as applied to one or more values of interest, refers to a value that is similar to a stated reference value. In certain embodiments, the term “approximately” or “about” refers to a range of values that fall within 25%, 20%, 19%, 18%, 17%, 16%, 15%, 14%, 13%, 12%, 11%, 10%, 9%, 8%, 7%, 6%, 5%, 4%, 3%, 2%, 1%, or less in either direction (greater than or less than) of the stated reference value unless otherwise stated or otherwise evident from the context (except where such number would exceed 100% of a possible value).

Conjugate: As used herein, and understood from the proper context, the terms “conjugate(s)” or “glycoconjugate(s)” refer to a Streptococcus pneumoniae polysaccharide conjugated to a carrier protein using any covalent or non-covalent bioconjugation strategy.

Excipient: As used herein, the term “excipient” refers to a non-therapeutic agent that may be included in a composition, for example to provide or contribute to a desired consistency or stabilizing effect.

Mixed carrier. As used herein, a mixed carrier, pneumococcal conjugate composition refers to a pneumococcal conjugate composition having more than one type of protein carrier.

Multivalent: As used herein, the term “multivalent” refers to a pneumococcal conjugate composition having pneumococcal capsular polysaccharides from more than one Streptococcus pneumoniae serotype.

Mixed carrier, 16-valent pneumococcal conjugate composition: As used herein, the term “mixed carrier, 16-valent pneumococcal conjugate composition(s)” refers to a composition comprising 16 different pneumococcal capsular polysaccharide-protein conjugates, wherein each pneumococcal capsular polysaccharide-protein conjugate comprises a protein carrier conjugated to a capsular polysaccharide from a different serotype of Streptococcus pneumoniae, wherein the Streptococcus pneumoniae serotypes are 1, 3, 4, 5, 6A, 6B, 7F, 9V, 12F, 14, 18C, 19A, 19F, 22F, 23F, and 33F, wherein the protein carrier is CRM₁₉₇ or tetanus toxoid, wherein two of the capsular polysaccharides are conjugated to tetanus toxoid and the remaining capsular polysaccharides are conjugated to CRM₁₉₇, and wherein the two capsular polysaccharides that are conjugated to tetanus toxoid are selected from the group consisting of serotypes 1, 3, and 5. In some embodiments, the capsular polysaccharides from serotypes 1 and 5 are conjugated to tetanus toxoid, and the capsular polysaccharides from the remaining serotypes are conjugated to CRM₁₉₇. In another embodiment, the capsular polysaccharides from serotypes 1 and 3 are conjugated to tetanus toxoid, and the remaining capsular polysaccharides are conjugated to CRM₁₉₇. In yet another embodiment, the capsular polysaccharides from serotypes 3 and 5 are conjugated to tetanus toxoid, and the remaining capsular polysaccharides are conjugated to CRM₁₉₇.

Pharmaceutically acceptable excipient: The pharmaceutically acceptable excipients useful in this disclosure are conventional. Remington's Pharmaceutical Sciences, by E. W. Martin, Mack Publishing Co., Easton, Pa., 15th Edition (1975), describes compositions and formulations suitable for pharmaceutical delivery of one or more therapeutic compositions, including vaccines, and additional pharmaceutical agents. Suitable pharmaceutical excipients include, for example, starch, glucose, lactose, sucrose, gelatin, malt, rice, flour, chalk, silica gel, sodium stearate, glycerol monostearate, talc, sodium chloride, dried skim milk, glycerol, propylene, glycol, water, ethanol and the like. In general, the nature of the excipient will depend on the particular mode of administration being employed. For instance, parenteral formulations usually comprise injectable fluids that include pharmaceutically and physiologically acceptable fluids such as water, physiological saline, balanced salt solutions, buffers, aqueous dextrose, glycerol or the like as a vehicle. For solid compositions (for example, powder, pill, tablet, or capsule forms), conventional non-toxic solid excipients can include, for example, pharmaceutical grades of mannitol, lactose, starch, or magnesium stearate. In addition to biologically-neutral carriers, pharmaceutical compositions to be administered can contain minor amounts of non-toxic auxiliary substances, such as wetting or emulsifying agents, a surface active agent, preservatives, and pH buffering agents and the like, for example sodium acetate or sorbitan monolaurate.

Prophylactically effective amount: As defined herein, the term “a prophylactically effective amount” or “a prophylactically effective dose” refers to the amount or dose required to induce an immune response sufficient to delay onset and/or reduce in frequency and/or severity one or more symptoms caused by an infection with Streptococcus pneumoniae.

Prophylaxis: The term “prophylaxis,” as used herein, refers to avoidance of disease manifestation, a delay of onset, and/or reduction in frequency and/or severity of one or more symptoms of a particular disease, disorder or condition (e.g., infection with Streptococcus pneumoniae). In some embodiments, prophylaxis is assessed on a population basis such that an agent is considered to provide prophylaxis against a particular disease, disorder or condition if a statistically significant decrease in the development, frequency, and/or intensity of one or more symptoms of the disease, disorder or condition is observed in a population susceptible to the disease, disorder, or condition.

Subject: As used herein, the term “subject” means any mammal, including mice, rabbits, and humans. In certain embodiments, the subject is an adult, an adolescent or an infant. In some embodiments, terms “individual” or “patient” are used and are intended to be interchangeable with “subject.”

DETAILED DESCRIPTION

The following description of the disclosed embodiment(s) and Examples is merely exemplary in nature and is in no way intended to limit the invention, its application, or uses.

This application provides new and improved mixed carrier, multivalent pneumococcal conjugate compositions and vaccines comprising the same. While the protein carrier, CRM₁₉₇, has previously been used in single carrier, pneumococcal conjugate vaccines, this application describes for the first time the use of CRM₁₉₇ in a mixed carrier, pneumococcal conjugate vaccine.

As discussed above, the immunogenicity of different capsular polysaccharide conjugates may vary depending on the pneumococcal serotype and carrier protein used. This application describes the successful conjugation of serotype 3 to tetanus toxoid as part of a mixed carrier vaccine, notwithstanding previous teachings that serotype 3 was more immunogenic when conjugated to diphtheria toxoid rather than tetanus toxoid [2, 6]. It also discloses the unexpected finding that the antibody response to serotype 3 conjugated to tetanus toxoid in a mixed carrier, 16-valent pneumococcal conjugate composition was about 4-fold higher than when serotype 3 was conjugated to CRM₁₉₇ in a single carrier, 13-valent pneumococcal conjugate composition (PREVNAR 13).

Further, the unexpected finding was not limited to serotype 3 but was also observed for the other serotypes conjugated to tetanus toxoid in the mixed carrier, 16-valent pneumococcal conjugate composition. As shown in the Examples, conjugation of serotypes 1 and 3, 1 and 5, or 3 and 5 to tetanus toxoid in a mixed carrier, pneumococcal conjugate composition with the remaining serotypes conjugated to CRM₁₉₇ (PVC16-13TT, PVC16-15TT, and PVC16-35TT, respectively) consistently induced significantly enhanced antibody responses to the serotypes conjugated to tetanus toxoid as compared to the antibody responses (IgG response or multiplex opsonophagocytic assay (MOPA) titers) against the same serotypes conjugated to CRM₁₉₇ in a single carrier, pneumococcal conjugate composition (PREVNAR 13), as summarized in the table below.

TABLE 1 Fold Increase in Antibody Response to Serotypes Conjugated to Tetanus Toxoid in Mixed Carrier Vaccine Compared to PREVNAR 13 Fold Increase in Antibody Response Compared to PREVNAR 13 Serotype PVC16-13TT PVC16-15TT PVC16-35TT 1 (IgG)  3X 3.9X N/A 1 (MOPA) 6.3X 6.3X N/A 3 (IgG) 5.5X N/A 2.8X 3 (MOPA)  4X N/A  4X 5 (IgG) N/A 8.7X 3.2X 5 (MOPA) N/A  5X  4X

The mixed carrier, 16-valent pneumococcal conjugate compositions described in this application also include pneumococcal serotypes not covered by the three pneumococcal conjugate vaccines currently available on the global market: PREVNAR (called Prevenar in some countries), SYNFLORIX and PREVNAR 13. Disease caused by pneumococcal serotypes not currently covered is on the rise, due, in part, to the development of antibacterial resistance, the increased number of immunocompromised patients, and lack of immune pressure. For example, none of the currently available pneumococcal conjugate vaccines includes serotype 12F. In addition, none of the currently available pneumococcal conjugate vaccines includes serotypes 22F and 33F. The present disclosure demonstrates the successful implementation of serotypes 12F, 22F, and 33F into a mixed carrier, pneumococcal conjugate vaccine.

Mixed Carrier, Multivalent Pneumococcal Conjugate Compositions and Methods of Making the Same

In one aspect, this disclosure provides a mixed carrier, multivalent pneumococcal conjugate composition comprising 16 different pneumococcal capsular polysaccharide-protein conjugates, wherein each pneumococcal capsular polysaccharide-protein conjugate comprises a protein carrier conjugated to a capsular polysaccharide from a different serotype of Streptococcus pneumoniae, wherein the Streptococcus pneumoniae serotypes are 1, 3, 4, 5, 6A, 6B, 7F, 9V, 12F, 14, 18C, 19A, 19F, 22F, 23F, and 33F, wherein the protein carrier is CRM₁₉₇ or tetanus toxoid, wherein two of the capsular polysaccharides are conjugated to tetanus toxoid and the remaining capsular polysaccharides are conjugated to CRM₁₉₇, and wherein the two capsular polysaccharides that are conjugated to tetanus toxoid are selected from the group consisting of serotypes 1, 3, and 5.

In some embodiments, the capsular polysaccharides from serotypes 1 and 5 are conjugated to tetanus toxoid, and the capsular polysaccharides from the remaining serotypes are conjugated to CRM₁₉₇. In another embodiment, the capsular polysaccharides from serotypes 1 and 3 are conjugated to tetanus toxoid, and the remaining capsular polysaccharides are conjugated to CRM₁₉₇. In yet another embodiment, the capsular polysaccharides from serotypes 3 and 5 are conjugated to tetanus toxoid, and the remaining capsular polysaccharides are conjugated to CRM₁₉₇.

In a polysaccharide-protein conjugate vaccine, a carrier protein is conjugated to a polysaccharide antigen primarily to help enhance the immune response (e.g. antibody response) to the polysaccharide antigen. Carrier proteins are preferably proteins that are non-toxic having little or no immunogenicity. Carrier proteins should be amenable to conjugation with a pneumococcal polysaccharide using standard conjugation procedures, as discussed in further detail below. The carrier proteins used in the mixed carrier, 16-valent pneumococcal conjugate compositions are tetanus toxoid (TT) and CRM₁₉₇, each of which has been used in the design of pneumococcal conjugate vaccines but never in the same, mixed carrier vaccine.

CRM₁₉₇ is a non-toxic variant (i.e., toxoid) of diphtheria toxin that retains the immunologic properties of the wild type diphtheria toxin. CRM₁₉₇ differs from the wild type diphtheria toxin at a single base in the structural gene, which gives rise to a single amino acid substitution from glutamic acid to glycine. CRM₁₉₇ is typically isolated from cultures of Corynebacterium diphtheria strain C7 (β197) grown on casamino acids and yeast extract-based medium. CRM₁₉₇ may be purified through ultra-filtration, ammonium sulfate precipitation, and ion-exchange chromatography. Alternatively, CRM₁₉₇ can be prepared recombinantly in accordance with U.S. Pat. No. 5,614,382, which is hereby incorporated by reference in its entirety. CRM₁₉₇ has been used in the design of pneumococcal conjugate vaccines but never as part of a mixed carrier vaccine.

Tetanus toxoid is prepared and used worldwide for large-scale immunization against tetanus (or lockjaw) caused by Clostridium tetani. Tetanus toxoid is also used both singly and in combination with diphtheria and/or pertussis vaccines. The parent protein, tetanus toxin, is generally obtained in cultures of Clostridium tetani. Tetanus toxin is a protein of about 150 kDa and consists of two subunits (about 100 kDa and about 50 kDa) linked by a sulfide bond. The toxin is typically detoxified with formaldehyde and can be purified from culture filtrates using known methods, such as ammonium sulfate precipitation (see, e.g., [7], [8]) or chromatography techniques, as disclosed, for example, in WO 1996/025425. Tetanus toxin may also be inactivated by recombinant genetic means.

Tetanus toxoid has also been used as a carrier protein in other vaccines, including pneumococcal conjugate vaccines. But it has never been used in a mixed carrier, pneumococcal conjugate vaccine in combination with CRM₁₉₇. The art also teaches away from conjugating serotype 3 to tetanus toxoid in a mixed carrier, pneumococcal conjugate vaccine because serotype 3 was shown to be more immunogenic when conjugated to diphtheria toxoid as compared to tetanus toxoid [2, 6].

The pneumococcal capsular polysaccharides used in the compositions and vaccines described herein, including the capsular polysaccharides from serotypes 1, 3, 4, 5, 6A, 6B, 7F, 9V, 12F, 14, 18C, 19A, 19F, 22F, 23F, and 33F, may be prepared from Streptococcus pneumoniae using any available technique, including standard techniques known to one of ordinary skill in the art, including, for example, those disclosed in WO 2006/110381, WO 2008/118752, WO 2006/110352, and U.S. Patent App. Pub. Nos. 2006/0228380, 2006/0228381, 2007/0184071, 2007/0184072, 2007/0231340, 2008/0102498 and 2008/0286838, all of which are incorporated by reference in their entireties. For example, each pneumococcal capsular polysaccharide serotype may be grown in culture medium (e.g., a soy-based medium). The cells are lysed, and individual polysaccharides may be purified from the lysate through centrifugation, precipitation, ultra-filtration, and/or column chromatography. In addition, the pneumococcal capsular polysaccharide can be produced using synthetic protocols.

Capsular polysaccharides of Streptococcus pneumoniae comprise repeating oligosaccharide units, which may contain up to 8 sugar residues. A capsular saccharide antigen may be a full length polysaccharide, or it may be reduced in size (e.g., a single oligosaccharide unit, or a shorter than native length saccharide chain of repeating oligosaccharide units). The size of capsular polysaccharides may be reduced by various methods known in the art, such as acid hydrolysis treatment, hydrogen peroxide treatment, sizing by a high pressure homogenizer, optionally followed by a hydrogen peroxide treatment to generate oligosaccharide fragments, or microfluidization.

The pneumococcal conjugate of each of the serotypes may be prepared by conjugating a capsular polysaccharide of each serotype to a carrier protein. The different pneumococcal conjugates may be formulated into a composition, including a single dosage formulation.

To prepare a polysaccharide-protein conjugate, the capsular polysaccharides prepared from each pneumococcal serotype may be chemically activated so that the capsular polysaccharides may react with a carrier protein. Once activated, each capsular polysaccharide may be separately conjugated to a carrier protein to form a glycoconjugate. The chemical activation of the polysaccharides and subsequent conjugation to the carrier protein may be achieved by conventional methods. For example, vicinal hydroxyl groups at the end of the capsular polysaccharides can be oxidized to aldehyde groups by oxidizing agents such as periodates (including sodium periodate, potassium periodate, or periodic acid), as disclosed, for example, in U.S. Pat. Nos. 4,365,170, 4,673,574 and 4,902,506, which are hereby incorporated by reference in their entireties. Polysaccharides may also be activated with 1-cyano-4-dimethylamino pyridinium tetrafluoroborate (CDAP) to form a cyanate ester. The activated polysaccharide is then coupled directly or via a spacer or linker group to an amino group on the carrier protein.

For example, the spacer could be cystamine or cysteamine to give a thiolated polysaccharide which could be coupled to the carrier via a thioether linkage obtained after reaction with a maleimide-activated carrier protein (for example using N-[y-maleimidobutyrloxy]succinimide ester (GMBS)) or a haloacetylated carrier protein (for example using iodoacetimide, N-succinimidyl bromoacetate (SBA; SIB), N-succinimidyl(4-iodoacetyl)aminobenzoate (SIAB), sulfosuccinimidyl(4-iodoacetyl)aminobenzoate (sulfo-SIAB), N-succinimidyl iodoacetate (SIA) or succinimidyl 3-[bromoacetamido]proprionate (SBAP)). Preferably, the cyanate ester (optionally made by COAP chemistry) is coupled with hexane diamine or adipic acid dihydrazide (AOH) and the amino-derivatized saccharide is conjugated to the carrier protein using carbodiimide (e.g., EOAC or EOC) chemistry via a carboxyl group on the protein carrier. Such conjugates are described for example in WO 93/15760, WO 95/08348 and WO 96/129094.

The conjugation of the activated capsular polysaccharides and the carrier proteins may be achieved, for example, by reductive amination, as described, for example, in U.S. Patent Appl. Pub. Nos. 2006/0228380, 2007/0231340, 2007/0184071 and 2007/0184072, WO 2006/110381, WO 2008/079653, and WO 2008/143709, all of which are incorporated by reference in their entireties. For example, the activated capsular polysaccharides and the carrier protein may be reacted with a reducing agent to form a conjugate. Reducing agents which are suitable include borohydrides, such as sodium cyanoborohydride, borane-pyridine, sodium triacetoxyborohydride, sodium borohydride, or borohydride exchange resin. At the end of the reduction reaction, there may be unreacted aldehyde groups remaining in the conjugates. The unreacted aldehyde groups may be capped using a suitable capping agent, such as sodium borohydride (NaBH4). In an embodiment, the reduction reaction is carried out in aqueous solvent. In another embodiment the reaction is carried out in aprotic solvent. In an embodiment, the reduction reaction is carried out in DMSO (dimethylsulfoxide) or in DMF (dimethylformamide) solvent.

The activated capsular polysaccharides may be conjugated directly to the carrier protein or indirectly through the use of a spacer or linker, such as a bifunctional linker. The linker is optionally heterobifunctional or homobifunctional, having for example a reactive amino group and a reactive carboxylic acid group, 2 reactive amino groups or two reactive carboxylic acid groups.

Other suitable techniques for conjugation use carbodiimides, hydrazides, active esters, norborane, p-nitrobenzoic acid, N-hydroxysuccinimide, S-NHS, EOC, TSTU, as described, for example, in International Patent Application Publication No. WO 98/42721. Conjugation may involve a carbonyl linker which may be formed by reaction of a free hydroxyl group of the saccharide with 1,1′-carbonyldiimidazole (CDI) (see Bethell et al. (1979) J. Biol. Chem. 254:2572-2574; Hearn et al. (1981) J. Chromatogr. 218:509-518) followed by reaction with a protein to form a carbamate linkage. This may involve reduction of the anomeric terminus to a primary hydroxyl group, optional protection/deprotection of the primary hydroxyl group, reaction of the primary hydroxyl group with CDI to form a CDI carbamate intermediate and coupling the CDI carbamate intermediate with an amino group on a protein.

The ratio of polysaccharide to carrier protein for pneumococcal conjugate vaccines is typically in the range 0.3-3.0 (w/w) but can vary with the serotype. The ratio can be determined either by independent measurement of the amounts of protein and polysaccharide present, or by methods that give a direct measure of the ratio known in the art. Methods include ¹H NMR spectroscopy or the use of SEC-HPLC-UV/RI with dual monitoring (e.g. refractive index and UV, for total material and protein content respectively) can profile the saccharide/protein ratio over the size distribution of conjugates as well as by SEC-HPLC-MALLS or MALDI-TOF-MS.

The polysaccharide-protein conjugates thus obtained may be purified and enriched by a variety of methods. These methods include concentration/diafiltration, column chromatography, and depth filtration. The purified polysaccharide-protein conjugates are combined to formulate a mixed carrier, 16-valent pneumococcal conjugate composition, which can be used as a vaccine.

Formulation of a vaccine composition can be accomplished using art-recognized methods. A vaccine composition is formulated to be compatible with its intended route of administration. The individual pneumococcal capsular polysaccharide-protein conjugates can be formulated together with a physiologically acceptable vehicle to prepare the composition. Examples of such vehicles include, but are not limited to, water, buffered saline, polyols (e.g., glycerol, propylene glycol, liquid polyethylene glycol) and dextrose solutions.

In some embodiments, the mixed carrier, 16-valent pneumococcal conjugate composition further comprises an adjuvant. Adjuvants can include a suspension of minerals (alum, aluminum salts, such as aluminum hydroxide, aluminum phosphate, aluminum sulfate, aluminum hydroxyphosphate sulfate, etc.) on which antigen is adsorbed; or water-in-oil emulsion in which antigen solution is emulsified in mineral oil (for example, Freund's incomplete adjuvant), sometimes with the inclusion of killed mycobacteria (Freund's complete adjuvant) to further enhance antigenicity. Immunostimulatory oligonucleotides (such as those including a CpG motif) can also be used as adjuvants (for example, see U.S. Pat. Nos. 6,194,388; 6,207,646; 6,214,806; 6,218,371; 6,239,116; 6,339,068; 6,406,705; and 6,429,199). Adjuvants also include biological molecules, such as lipids and costimulatory molecules. Exemplary biological adjuvants include AS04 [9], IL-2, RANTES, GM-CSF, TNF-α, IFN-γ, G-CSF, LFA-3, CD72, B7-1, B7-2, OX-40L and 41 BBL.

In some embodiments, the adjuvant is an aluminum-based adjuvant.

In particular embodiments, the adjuvant is selected from the group consisting of aluminum phosphate, aluminum sulfate, and aluminum hydroxide.

In particular embodiments, the adjuvant is aluminum phosphate.

In some embodiments, the composition is for use as a vaccine against an infection of Streptococcus pneumoniae.

Prophylactic Methods and Uses

In one aspect, this disclosure provides a vaccine comprising a mixed carrier, 16-valent pneumococcal conjugate composition and a pharmaceutically acceptable excipient. In some embodiment, the pharmaceutically acceptable excipient comprises at least a buffer, such as a succinate buffer, a salt, such as sodium chloride, and/or a surface active agent, such as a polyoxyethylene sorbitan ester (e.g., polysorbate 80). In some embodiments, the capsular polysaccharides from serotypes 1 and 5 are conjugated to the tetanus toxoid, and the capsular polysaccharides from serotypes 3, 4, 6A, 6B, 7F, 9V, 12F, 14, 18C, 19A, 19F, 22F, 23F, and 33F are conjugated to CRM₁₉₇. In another embodiment, the capsular polysaccharides from serotypes 1 and 3 are conjugated to the tetanus toxoid, and the capsular polysaccharides from serotypes 4, 5, 6A, 6B, 7F, 9V, 12F, 14, 18C, 19A, 19F, 22F, 23F, and 33F are conjugated to CRM₁₉₇. In yet another embodiment, the capsular polysaccharides from serotypes 3 and 5 are conjugated to the tetanus toxoid, and the capsular polysaccharides from serotypes 1, 4, 6A, 6B, 7F, 9V, 12F, 14, 18C, 19A, 19F, 22F, 23F, and 33F are conjugated to CRM₁₉₇.

In some embodiments, the vaccine elicits a protective immune response in a human subject against disease caused by Streptococcus pneumoniae infection.

According to a further aspect, this disclosure provides a method for prophylaxis of Streptococcus pneumoniae infection or disease, the method comprising administering to a human subject a prophylactically effective amount of a mixed carrier, 16-valent pneumococcal conjugate composition or a vaccine comprising the same. The mixed carrier, 16-valent pneumococcal conjugate composition or vaccine comprising the same may be administered by any route, including, for example, by a systemic or mucosal route, as described below in further detail.

In certain embodiments, the human subject is an elderly subject and the disease is pneumonia or invasive pneumococcal disease (IPD). In certain embodiments, the elderly subject is at least 50 years old. In other embodiments, the elderly subject is at least 55 years old. In yet other embodiments, the elderly subject is at least 60 years old.

In other embodiments, the human subject is an infant and the disease is pneumonia, invasive pneumococcal disease (IPD), or acute otitis media (AOM). In certain embodiments, the infant is 0-2 years. In other embodiments, the infant is 2 to 15 months.

In yet another embodiment, the human subject is 6 weeks to 17 years of age and the disease is pneumonia, invasive pneumococcal disease (IPD) or acute otitis media (AOM). In certain embodiments, the human subject is 6 weeks to 5 years of age. In other embodiments, the human subject is 5 to 17 years of age.

The amount of conjugate in each vaccine dose or the prophylactically effective amount of the mixed carrier, multivalent pneumococcal conjugate composition may be selected as an amount that induces prophylaxis without significant, adverse effects. Such an amount can vary depending upon the pneumococcal serotype. Generally, each dose may include about 0.1 μg to about 100 μg of polysaccharide, specifically, about 0.1 to 10 μg, and, more specifically, about 1 μg to about 5 μg. Optimal amounts of components for a particular vaccine can be ascertained by standard studies involving observation of appropriate immune responses in subjects. For example, the amount for vaccination of a human subject can be determined by extrapolating an animal test result. In addition, the dose can be determined empirically.

In some embodiments, the vaccine or the mixed carrier, 16-valent pneumococcal conjugate composition may be a single 0.5 ml dose formulated to contain about 1 μg to about 5 μg of each capsular polysaccharide; about 1 μg to about 25 μg of TT; about 20 μg to about 75 μg of CRM₁₉₇, and optionally about 0.1 mg to about 0.5 mg of elemental aluminum adjuvant. In some embodiments, the vaccine or the mixed carrier, 16-valent pneumococcal conjugate composition may be a single 0.5 ml dose formulated to contain about 2 μg to about 2.5 μg of each capsular polysaccharide except serotype 6B; about 4 μg to about 5 μg of the capsular polysaccharide of serotype 6B; about 5 μg to about 15 μg of TT; about 30 μg to about 60 μg of CRM₁₉₇; and optionally about 0.1 mg to about 0.2 mg of elemental aluminum adjuvant. In certain embodiments, the mixed carrier, 16-valent pneumococcal conjugate composition or vaccine comprising the same further comprises sodium chloride and sodium succinate buffer as excipients.

In some embodiments, the mixed carrier, 16-valent pneumococcal conjugate composition may be formulated into a liquid formulation in which each of the pneumococcal capsular polysaccharides of serotypes 1 and 3 is conjugated to TT and each of the pneumococcal capsular polysaccharides serotypes 4, 5, 6A, 6B, 7F, 9V, 12F, 14, 18C, 19A, 19F, 22F, 23F, and 33F is conjugated to CRM₁₉₇. Each 0.5 mL dose may be formulated into a liquid containing: about 2.2 μg of each polysaccharide, except for 6B at about 4.4 μg; about 10 μg to about 15 μg of TT carrier protein (only for the serotypes 1 and 3) and about 40 μg to about 50 μg of CRM₁₉₇ carrier protein; 0.125 mg of elemental aluminum (0.5 mg aluminum phosphate) as an adjuvant; and sodium chloride and sodium succinate buffer as excipients.

In some embodiments, the mixed carrier, 16-valent pneumococcal conjugate composition may be formulated into a liquid formulation in which each of the pneumococcal capsular polysaccharides of serotypes 1 and 5 is conjugated to TT and each of the pneumococcal capsular polysaccharides serotypes 3, 4, 6A, 6B, 7F, 9V, 12F, 14, 18C, 19A, 19F, 22F, 23F, and 33F is conjugated to CRM₁₉₇. Each 0.5 mL dose may be formulated into a liquid containing: about 2.2 μg of each saccharide, except for 6B at about 4.4 μg; about 5 μg to about 10 μg of TT carrier protein (only for the serotypes 1 and 5) and about 40 μg to about 50 μg of CRM₁₉₇ carrier protein; about 0.125 mg of elemental aluminum (0.5 mg aluminum phosphate) adjuvant; and sodium chloride and sodium succinate buffer as excipients.

In some embodiments, the mixed carrier, 16-valent pneumococcal conjugate composition may be formulated into a liquid formulation in which each of the pneumococcal capsular polysaccharides of serotypes 3 and 5 is conjugated to TT and each of the pneumococcal capsular polysaccharides serotypes 1, 4, 6A, 6B, 7F, 9V, 12F, 14, 18C, 19A, 19F, 22F, 23F, and 33F is conjugated to CRM₁₉₇. Each 0.5 mL dose may be formulated into a liquid containing: about 2.2 μg of each saccharide, except for 6B at about 4.4 μg; about 10 μg to about 15 μg of TT carrier protein (only for the serotypes 3 and 5) and about 40 μg to about 50 μg of CRM₁₉₇ carrier protein; about 0.125 mg of elemental aluminum (0.5 mg aluminum phosphate) adjuvant; and sodium chloride and sodium succinate buffer as excipients.

In some embodiments, the liquid formulation may be filled into a single dose syringe without a preservative. After shaking, the liquid formulation becomes a vaccine that is a homogeneous, white suspension ready for intramuscular administration.

The mixed carrier, 16-valent pneumococcal conjugate composition can be administered in a single injection or as part of an immunization series. For example, the mixed carrier, 16-valent pneumococcal conjugate composition can be administered 2, 3, 4, or more times at appropriately spaced intervals, such as, a 1, 2, 3, 4, 5, or 6 month interval or a combination thereof. In some embodiments, the mixed carrier, 16-valent pneumococcal conjugate composition is administered to an infant 4 times within the first 15 months of birth, including, for example, at about 2, 3, 4, and 12-15 months of age; at about 3, 4, 5, and 12-15 months of age; or at about 2, 4, 6, and 12 to 15 months of age. This first dose can be administered as early as 6 weeks of age. In another embodiment, the mixed carrier, 16-valent pneumococcal conjugate composition is administered to an infant 3 times within the first 15 months of birth, including, for example, at about 2, 4, and 11-12 months.

The mixed carrier, multivalent pneumococcal conjugate composition may also include one or more proteins from Streptococcus pneumoniae. Examples of Streptococcus pneumoniae proteins suitable for inclusion include those identified in International Patent Application WO02/083855, as well as those described in International Patent Application WO02/053761.

The mixed carrier, 16-valent pneumococcal conjugate composition can be administered to a subject via one or more administration routes known to one of ordinary skill in the art such as a parenteral, transdermal, or transmucosal, intranasal, intramuscular, intraperitoneal, intracutaneous, intravenous, or subcutaneous route and be formulated accordingly. The mixed carrier, 16-valent pneumococcal conjugate composition can be formulated to be compatible with its intended route of administration.

In some embodiments, the mixed carrier, 16-valent pneumococcal conjugate composition can be administered as a liquid formulation by intramuscular, intraperitoneal, subcutaneous, intravenous, intraarterial, or transdermal injection or respiratory mucosal injection. The mixed carrier, 16-valent pneumococcal conjugate compositions can be formulated in liquid form or in a lyophilized form. In some embodiments, injectable compositions are prepared in conventional forms, either as liquid solutions or suspensions, solid forms suitable for solution or suspension in liquid prior to injection, or as emulsions. In some embodiments, injection solutions and suspensions are prepared from sterile powders or granules. General considerations in the formulation and manufacture of pharmaceutical agents for administration by these routes may be found, for example, in Remington's Pharmaceutical Sciences, 19^(th) ed., Mack Publishing Co., Easton, Pa., 1995; incorporated herein by reference. At present the oral or nasal spray or aerosol route (e.g., by inhalation) are most commonly used to deliver therapeutic agents directly to the lungs and respiratory system. In some embodiments, a mixed carrier, 16-valent pneumococcal conjugate composition is administered using a device that delivers a metered dosage of composition. Suitable devices for use in delivering intradermal pharmaceutical compositions described herein include short needle devices such as those described in U.S. Pat. Nos. 4,886,499, 5,190,521, 5,328,483, 5,527,288, 4,270,537, 5,015,235, 5,141,496, 5,417,662 (all of which are incorporated herein by reference). Intradermal compositions may also be administered by devices which limit the effective penetration length of a needle into the skin, such as those described in WO1999/34850, incorporated herein by reference, and functional equivalents thereof. Also suitable are jet injection devices which deliver liquid vaccines to the dermis via a liquid jet injector or via a needle which pierces the stratum corneum and produces a jet which reaches the dermis. Jet injection devices are described for example in U.S. Pat. Nos. 5,480,381, 5,599,302, 5,334,144, 5,993,412, 5,649,912, 5,569,189, 5,704,911, 5,383,851, 5,893,397, 5,466,220, 5,339,163, 5,312,335, 5,503,627, 5,064,413, 5,520,639, 4,596,556, 4,790,824, 4,941,880, 4,940,460, WO1997/37705, and WO1997/13537 (all of which are incorporated herein by reference). Also suitable are ballistic powder/particle delivery devices which use compressed gas to accelerate vaccine in powder form through the outer layers of the skin to the dermis. Additionally, conventional syringes may be used in the classical mantoux method of intradermal administration.

Preparations for parenteral administration include sterile aqueous or nonaqueous solutions, suspensions, and emulsions. Examples of non-aqueous solvents are propylene glycol, polyethylene glycol, oils such as olive oil, and injectable organic esters such as ethyl oleate. Examples of oil include vegetable or animal oil, peanut oil, soybean oil, olive oil, sunflower oil, liver oil, synthetic oil such as marine oil, and lipids obtained from milk or eggs. Aqueous carriers include water, alcoholic/aqueous solutions, emulsions or suspensions, including saline and buffered media. Parenteral vehicles include sodium chloride solution, Ringer's dextrose, dextrose and sodium chloride, lactated Ringer's, or fixed oils. Intravenous vehicles include fluid and nutrient replenishers, electrolyte replenishers (such as those based on Ringer's dextrose), and the like. Preservatives and other additives may also be present such as, for example, antimicrobials, anti-oxidants, chelating agents, and inert gases and the like.

The mixed carrier, 16-valent pneumococcal conjugate composition can be formulated in the form of a unit dose vial, multiple dose vial, or pre-filled syringe. A pharmaceutically acceptable carrier for a liquid formulation includes aqueous or nonaqueous solvent, suspension, emulsion, or oil. The composition may be isotonic, hypertonic, or hypotonic. However, it is desirable that the composition for infusion or injection is basically isotonic. Thus, isotonicity or hypertonicity may be advantageous for storage of the composition. When the composition is hypertonic, the composition can be diluted to isotonicity before administration. A tonicity agent may be ionic tonicity agent such as salt or non-ionic tonicity agent such as carbohydrate. The ionic tonicity agent includes, but is not limited to, sodium chloride, calcium chloride, potassium chloride, and magnesium chloride. The nonionic tonicity agent includes, but is not limited to, sorbitol and glycerol. Preferably, at least one pharmaceutically acceptable buffer is included. For example, when the composition is an infusion or injection, it is preferable to be formulated in a buffer with a buffering capacity at pH 4 to pH 10, such as pH 5 to pH 9, or, pH 6 to pH 8. The buffer may be selected from those suitable for United States Pharmacopeia (USP). For example, the buffer can be selected from the group consisting of a monobasic acid, such as acetic acid, benzoic acid, gluconic acid, glyceric acid, and lactic acid; a dibasic acid, such as aconitic acid, adipic acid, ascorbic acid, carbonic acid, glutamic acid, malic acid, succinic acid, and tartaric acid; a polybasic acid such as citric acid and phosphoric acid; and a base such as ammonia, diethanolamine, glycine, triethanolamine, and TRIS.

The mixed carrier, 16-valent pneumococcal conjugate composition may comprise a surface active agent. Examples of the surface active agent include, but are not limited to, polyoxyethylene sorbitan ester (generally referred to as Tweens), in particular, polysorbate 20 and polysorbate 80; copolymers (such as DOWFAX) of ethylene oxide (EO), propylene oxide (PO), butylenes oxide (BO); octoxynols with different repeats of ethoxy(oxy-1,2-ethanediyl) group, in particular, octoxynol-9 (Triton-100); ethylphenoxypolyethoxyethanol (IGEPAL CA-630/NP-40); phospholipid such as lecithin; nonylphenol ethoxylate such as TERGITOL NP series; lauryl, cetyl, stearyl, oleyl alcohol-derived polyoxyethylene fatty ether (Brij surfactant), in particular, triethyleneglycol monolauryl ether (Brij 30); sorbitan ether known as SPAN, in particular, sorbitan trioleate (Span 85) and sorbitan monolaurate.

Mixtures of surface active agents such as Tween 80/Span 85 can be used. A combination of polyoxyethylene sorbitan ester such as Tween 80 and octoxynol such as Triton X-100 is also suitable. A combination of Laureth 9 and Tween and/or octoxynol is also advantageous. Preferably, the amount of polyoxyethylene sorbitan ester (such as Tween 80) included may be 0.01% to 1% (w/v), 0.01% to 0.1% (w/v), 0.01% to 0.05% (w/v), or about 0.02%; the amount of octylphenoxy polyoxyethanol or nonylphenoxy polyoxyethanol (such as Triton X-100) included may be 0.001% to 0.1% (w/v), in particular 0.005% to 0.02%; and the amount of polyoxyethylene ether (such as Laureth 9) included may be 0.1% to 20% (w/v), possibly 0.1% to 10%, in particular 0.1% to 1% or about 0.5%.

In some embodiments, the mixed carrier, 16-valent pneumococcal conjugate composition may be delivered via a release control system. For example, intravenous infusion, transdermal patch, liposome, or other routes can be used for administration. In one aspect, macromolecules such as microsphere or implant can be used.

The above disclosure generally describes the present invention. A more complete understanding can be obtained by reference to the following specific examples. These examples are described solely for the purpose of illustration and are not intended to limit the scope of the invention.

EXAMPLES Example 1. Preparation of S. pneumoniae Capsular Polysaccharides

Cultivation of S. pneumoniae and purification of capsular polysaccharides were conducted as known to one of skill in the art. S. pneumoniae serotypes were obtained from the American Type Culture Collection (ATCC) (serotype 1: ATCC No. 6301; serotype 3: ATCC No. 6303; serotype 4: ATCC No. 6304; serotype 5: ATCC No. 6305; serotype 6A: ATCC No. 6306; serotype 6B: ATCC No. 6326; serotype 7F: ATCC No. 10351; serotype 9V: ATCC No. 10368; serotype 12F: ATCC No. 6312; serotype 14: ATCC No. 6314; serotype 18C: ATCC No. 10356; serotype 19A: ATCC No. 10357; serotype 19F: ATCC No. 6319; serotype 22F: ATCC No. 6322; serotype 23F: ATCC No. 6323; serotype 33F: ATCC No. 10370). S. pneumoniae were characterized by capsules and immobility, Gram-positive, lancet-shaped diplococcus, and alpha hemolysis in a blood agar medium. Serotypes were identified by Quelling test using specific anti-sera (U.S. Pat. No. 5,847,112).

Preparation of Cell Banks

Several generations of seed stocks were generated in order to expand the strains and remove components of animal origin (generations F1, F2, and F3). Two additional generations of seed stocks were produced. The first additional generation was cultured from an F3 vial, and the subsequent generation was cultured from a vial of the first additional generation. Seed vials were stored frozen (below −70° C.) with synthetic glycerol as a cryopreservative. For cell bank preparation, all cultures were grown in a soy-based medium. Prior to freezing, cells were concentrated by centrifugation, spent medium was removed, and cell pellets were re-suspended in a fresh medium containing a cryopreservative (such as synthetic glycerol).

Culturing and Harvesting

Cultures from the working cell bank were inoculated into seed bottles containing a soy-based medium and cultured. After the target optical density (absorbance) was reached, the seed bottle was used to inoculate a fermentor containing the soy-based medium. The culturing was terminated when an optical density value started to be maintained constant. After terminating the culturing, sodium deoxycholate was added to the culture to lyse the cells. The resulting fermentor contents were cooled, and protein precipitation was induced. Then, the mixture was centrifuged to remove precipitated proteins and cell debris.

Purification

The solution obtained from the centrifugation was filtered through a depth filter to remove the proteins and cell debris that had not precipitated in the centrifugation. The filtrate was concentrated on a 100 kDa MW membrane and the concentrate was diafiltered with 10 volumes of a 25 mM sodium phosphate buffer (pH 7.2) to obtain a sample. The sample was filtered to collect a supernatant from which polysaccharides were precipitated and filtered. The filtrate was concentrated on a 30 kDa membrane, and the concentrate was diafiltered using about 10 volumes of triple distilled water. After performing the diafiltration, the remaining solution was filtered through a 0.2 μm filter. An in-process control test was performed on the filtrate (appearance, remaining proteins, remaining nucleic acids, endotoxins, molecular weights, and the total amount of polysaccharides). The concentrate was sterile filtered and stored at −20° C.

Example 2. Preparation of Conjugate of S. pneumoniae Capsular Polysaccharide and Carrier Protein

Polysaccharides of different serotypes were activated following different pathways and then conjugated to a carrier protein, CRM₁₉₇ or TT. Specifically, conjugates were prepared by conjugating each of the capsular polysaccharides of all serotypes to CRM₁₉₇ and by conjugating each of the capsular polysaccharides of the serotypes 1, 3, and 5 to TT. The activation process includes reduction of the size of each capsular polysaccharide to the target molecular weight, chemical activation, and buffer exchange via ultrafiltration. The conjugates were purified using ultrafiltration and finally filtered through 0.2 μm filter. The process parameters such as pH, temperature, concentration, and time were as follows.

(1) Activation Process

Step 1: Hydrolysis

Reductive amination is a known method for conjugating polymers in which an amide bond is formed between a primary amine (—NH₂) group of a protein and an aldehyde of a saccharide. However, since S. pneumoniae polysaccharides do not have any aldehyde groups, an aldehyde group is added to the pneumococcal capsular polysaccharide. A diol structure of a monosaccharide can be oxidized by sodium periodate (NaIO₄) to form an aldehyde group. The capsular polysaccharides from serotypes 1, 3, 4, 6A, 12F, 14, 18C, 22F, and 33F were pre-treated as follows.

In the case of the serotype 1, sodium hydroxide (at a final base concentration of 0.05 M) was added to a solution of the capsular polysaccharide, and the solution was incubated at 50±2° C. The solution was then cooled to a temperature in a range of about 21° C. to about 25° C., and hydrochloric acid was added thereto to a final pH of 6.0±0.1, thereby stopping hydrolysis.

In the case of the serotype 3, hydrochloric acid (at a final acid concentration of 0.01 M) was added to a solution of the capsular polysaccharide, and the solution was incubated at 60±2° C. The solution was then cooled to a temperature in a range of about 21° C. to about 25° C., and 0.1M sodium phosphate was added thereto to a final pH of 6.0±0.1, thereby stopping hydrolysis.

In the case of the serotype 4, hydrochloric acid (at a final acid concentration of 0.1 M) was added to a solution of the capsular polysaccharide, and the solution was incubated at 45±2° C. The solution was then cooled to a temperature in a range of about 21° C. to about 25° C., and 1M sodium phosphate was added thereto to a final pH of 6.0±0.1, thereby stopping hydrolysis.

In the case of the serotype 6A, glacial acetic acid (at a final acid concentration of 0.1 M) was added to a solution of the capsular polysaccharide, and the solution was incubated at 60±2° C. The solution was then cooled to a temperature in a range of about 21° C. to about 25° C., and 1M sodium hydroxide was added thereto to a final pH of 6.0±0.1.

In the case of the serotype 12F, hydrochloric acid (at a final acid concentration of 0.01 M) was added to a solution of the capsular polysaccharide, and the solution was incubated at 70±2° C. The solution was then cooled to a temperature in a range of about 21° C. to about 25° C., and 0.1M sodium phosphate was added thereto to a final pH of the solution of 6.0±0.1, thereby stopping hydrolysis.

In the case of the serotypes 14 and 18C, glacial acetic acid (at a final acid concentration of 0.2 M) was added to a solution of the capsular polysaccharide, and the solution was incubated at about 91-96° C. The solution was then cooled to a temperature in a range of about 21° C. to about 25° C., and 1M sodium phosphate was added thereto so that a final pH of the solution was 6.0±0.1.

In the case of the serotypes 22F and 33F, hydrochloric acid (at a final acid concentration of 0.01 M) was added to a solution of the capsular polysaccharide, and the solution was incubated at 60±2° C. The solution was then cooled to a temperature in a range of about 21° C. to about 25° C., and 0.1M sodium phosphate was added thereto to a final pH of 6.0±0.1, thereby stopping hydrolysis.

Each of the obtained capsular polysaccharides was diluted in water for injection (WFI), sodium acetate, and sodium phosphate to a final concentration between about 1.0 mg/mL and about 2.0 mg/mL.

Step 2: Periodate Reaction

The sodium periodate molar equivalent for each pneumococcal saccharide activation was determined using total saccharide content. With thorough mixing, the oxidation reaction was allowed to proceed for 16 to 20 hours at 21° C. to 25° C. for all serotypes except for 1, 7F, and 19F, for which the temperature was 10° C. or less. During the conjugation process, maintaining an aldehyde concentration at an appropriate level provides for consistent and stable production of conjugates. A degree of production of the aldehyde is determined by a ratio between a concentration of the produced aldehyde and a concentration of saccharide, and this degree is related to a degree of oxidation (Do) which is set for each serotype as shown in Table 2 and Table 3.

TABLE 2 Range of Do for all serotypes to be conjugated to CRM₁₉₇ Serotype Range of Do Serotype 1 4 to 10 Serotype 3 2 to 8 Serotype 4 1 to 5 Serotype 5 2 to 6 Serotype 6A 5 to 15 Serotype 6B 7 to 13 Serotype 7F 2 to 8 Serotype 9V 4 to 9 Serotype 12F 1 to 9 Serotype 14 6 to 13 Serotype 18C 6 to 14 Serotype 19A 7 to 13 Serotype 19F 6 to 12 Serotype 22F 1 to 16 Serotype 23F 6 to 14 Serotype 33F 1 to 15

TABLE 3 Range of Do for serotypes 1, 3, and 5 to be conjugated to TT Serotype Range of Do Serotype 1 1 to 15 Serotype 3 2 to 14 Serotype 5 1 to 15

Step 3: Ultrafiltration

The oxidized saccharide was concentrated and diafiltered with WFI on a 100 kDa MWCO ultrafilter (30 kDa ultrafilter for serotype 1 and 5 kDa ultrafilter for serotype 18C). Diafiltration was conducted using 0.9% sodium chloride solution for serotype 1, 0.01 M sodium acetate buffer (pH 4.5) for serotypes 7F and 23F and 0.01 M sodium phosphate buffer (pH 6.0) for serotype 19F. The permeate was discarded, and the retentate was filtered through a 0.2 μm filter.

Step 4: Lyophilization

For capsular polysaccharides of serotypes 3, 4, 5, 9V, 14, 22F, and 33F that are to be conjugated to a carrier protein by using an aqueous solvent, a mixed solution of polysaccharides and carrier protein was prepared without addition of sucrose, lyophilized, and then stored at −25° C.±5° C.

For capsular polysaccharides of serotypes 1 and 18C that are to be conjugated to a carrier protein by using an aqueous solvent, polysaccharides and carrier protein were independently prepared without addition of sucrose, lyophilized, and then stored at −25° C.±5° C.

For capsular polysaccharides of serotypes 6A, 6B, 7F, 19A, 19F, and 23F that are to be conjugated to a carrier protein by using a DMSO solvent, a predetermined amount of sucrose to reach a final sucrose concentration of 5%±3% was added to the activated saccharides, and the samples were independently prepared, lyophilized, and then stored at −25° C.±5° C.

For capsular polysaccharide of serotype 12F, a predetermined amount of sucrose to reach a final sucrose concentration of 10%±5% was added to the activated saccharide, and the sample were filled into glass bottles, lyophilized, and then stored at −25° C.±5° C.

(2) Conjugation Process

Aqueous conjugation was conducted for serotypes 1, 3, 4, 5, 9V, 14, 18C, 22F, and 33F, and DMSO conjugation was conducted for serotypes 6A, 6B, 7F, 12F, 19A, 19F, and 23F. Each of the capsular polysaccharides was conjugated to a carrier protein at a ratio of 0.2 to 2:1.

Step 1: Dissolution

Aqueous Conjugation

For serotypes 1, 3, 4, 5, 9V, 14, 18C, 22F, and 33F, the lyophilized sample was thawed and equilibrated at room temperature. The lyophilized sample was reconstituted to a reaction concentration by using a sodium phosphate buffer solution at 23° C.±2° C. at a ratio set for each serotype.

Dimethyl Sulfoxide (DMSO) Conjugation

For serotypes 6A, 6B, 7F, 12F, 19A, 19F, and 23F, the lyophilized sample was thawed, equilibrated at room temperature, and reconstituted in DMSO.

Step 2: Conjugation Reaction

Aqueous Conjugation

For serotypes 1, 3, 4, 5, 9V, 14, 18C, 22F, and 33F to be conjugated to CRM₁₉₇, the conjugation reaction was initiated by adding the sodium cyanoborohydride solution (100 mg/mL) to 1.0 to 1.4 moles sodium cyanoborohydride per mole of saccharide. However, for serotypes 1 and 3, the reaction was initiated by adding the sodium cyanoborohydride solution to 0.5 moles sodium cyanoborohydride per mole of saccharide.

For serotypes 1, 3, and 5 to be conjugated to TT, the conjugation reaction was initiated by adding the sodium cyanoborohydride solution (100 mg/mL) to 1.0 to 1.4 moles sodium cyanoborohydride per mole of saccharide, except for serotype 1 to 0.5 moles sodium cyanoborohydride per mole of saccharide.

The reaction mixture was incubated at 23° C. to 37° C. for 44 to 106 hours. The reaction temperature and time were adjusted by serotype. The temperature was then reduced to 23° C.±2° C. and sodium chloride 0.9% was added to the reactor. Sodium borohydride solution (100 mg/mL) was added to achieve 1.8 to 2.2 molar equivalents of sodium borohydride per mole of saccharide. The mixture was incubated at 23° C.±2° C. for 3 to 6 hours. This procedure reduced any unreacted aldehydes present on the saccharides. Then, the mixture was diluted with sodium chloride 0.9% and the diluted conjugation mixture was filtered using a 0.8 or 0.45 μm pre-filter.

DMSO Conjugation

For capsular polysaccharides of serotypes 6A, 6B, 7F, 12F, 19A, 19F, and 23F, the conjugation reaction was initiated by adding the sodium cyanoborohydride solution (100 mg/mL) to a ratio of 0.8 to 1.2 molar equivalents of sodium cyanoborohydride per one mole of activated saccharide. WFI was added to the reaction mixture to a target concentration of 1% (v/v), and the mixture was incubated for 12 to 26 hours at 23° C.±2° C. 100 mg/mL of a sodium borohydride solution (typical 1.8 to 2.2 molar equivalents sodium borohydride per mole activated saccharide) and WFI (target 5% v/v) were added to the reaction and the mixture was incubated for 3 to 6 hours at 23° C.±2° C. This procedure reduced any unreacted aldehydes present on the saccharides. Then, the reaction mixture was diluted with sodium chloride 0.9%, and the diluted conjugation mixture was filtered using a 0.8 or 0.45 μm pre-filter.

Step 3: Ultrafiltration

The diluted conjugate mixture was concentrated and diafiltered on a 100 kDa MWCO ultrafiltration filter or a 300 kDa MWCO ultrafiltration filter with a minimum of 15 volumes of 0.9% sodium chloride or buffer. Also, a type and pH of the buffer used in the process varied depending on each of the serotypes.

Step 4: Sterile Filtration

The retentate after the ultrafiltration was sterile filtered (0.2 μm), and in-process controls (appearance, free protein, free saccharide, molecular size distribution, sterility, saccharide content, protein content, pH, endotoxin, residual cyanide, residual DMSO, saccharide identity, TT identity, and CRM₁₉₇ identity) were performed on the filtered conjugates. The final concentrate was refrigerated and stored at 2° C. to 8° C.

Example 3. Formulation of Multivalent Pneumococcal Conjugate Vaccine

The desired volumes of final bulk concentrates obtained from Example 2 were calculated based on the batch volume and the bulk saccharide concentrations. After the 0.85% sodium chloride (physiological saline), polysorbate 80, and succinate buffer were added to the pre-labeled formulation vessel, bulk concentrates were added. The preparation was then thoroughly mixed and sterile filtered through a 0.2 μm membrane. The formulated bulk was mixed gently during and following the addition of bulk aluminum phosphate. The pH was checked and adjusted if necessary. The formulated bulk product was stored at 2° C. to 8° C. The following four types of multivalent pneumococcal conjugate vaccine formulations were prepared and named PCV16-CRM₁₉₇, PCV16-13TT, PCV16-15TT, and PCV16-35TT, respectively.

PCV16-CRM₁₉₇ included polysaccharide-conjugates prepared by conjugating each of polysaccharides of 16 serotypes (serotypes 1, 3, 4, 5, 6A, 6B, 7F, 9V, 12F, 14, 18C, 19A, 19F, 22F, 23F, and 33F) to CRM₁₉₇;

PCV16-13TT included polysaccharide-conjugates prepared by conjugating each polysaccharide of the serotypes 1 and 3 to TT and each polysaccharide of the serotypes 4, 5, 6A, 6B, 7F, 9V, 12F, 14, 18C, 19A, 19F, 22F, 23F, and 33F to CRM₁₉₇;

PCV16-15TT included polysaccharide-conjugates prepared by conjugating each polysaccharide of the serotypes 1 and 5 to TT and each polysaccharide of the serotypes 3, 4, 6A, 6B, 7F, 9V, 12F, 14, 18C, 19A, 19F, 22F, 23F, and 33F to CRM₁₉₇; and

PCV16-35TT included polysaccharide-conjugates prepared by conjugating each polysaccharide of the serotypes 3 and 5 to TT and each polysaccharide of the serotypes 1, 4, 6A, 6B, 7F, 9V, 12F, 14, 18C, 19A, 19F, 22F, 23F, and 33F to CRM₁₉₇.

The PCV16-13TT and PCV16-35TT vaccine composition obtained included 2.2 μg of each saccharide, except for serotype 6B at 4.4 μg; 10 ug to 15 ug of TT (for serotypes 1 and 3) and 40 μg to 50 μg of CRM₁₉₇; 0.125 mg of elemental aluminum (0.5 mg aluminum phosphate) adjuvant; 4.25 mg of sodium chloride; about 295 μg of a succinate buffer solution; and about 100 μg of polysorbate 80 in the total of 0.5 ml dose. The PCV16-15TT composition in a total dose of 0.5 mL included 5 μg to 10 μg of TT and 40 μg to 50 μg CRM₁₉₇, and, respectively, with the other components and contents thereof identical to those of PCV16-13TT and PCV16-35TT.

Example 4. Immunogenicity of Multivalent Pneumococcal Conjugate Vaccine

The mixed carrier, multivalent pneumococcal vaccines, PCV16-CRM₁₉₇, PCV16-13TT, PCV16-15TT, and PCV16-35TT prepared in Example 3, were tested for the ability to induce an immunogenic response in rabbits. These immunogenic effects were characterized by antigen-specific ELISA for serum IgG concentrations and by opsonophagocytic assay (OPA) for antibody function. New Zealand White rabbits were immunized intramuscularly at week 0 and week 3 with a dose of 5% higher than the planned human clinical dose of each polysaccharide (2.31 μg of each polysaccharide, except for 6B at 4.62 μg) in the formulation or the human dose (2.2 ug of each polysaccharide, except for 6B at 4.4 ug). Sera were sampled every 3 weeks post immunization. Both concentrations showed the same results.

A serotype-specific immune reaction with respect to PCV16-CRM₁₉₇, PCV16-13TT, PCV16-15TT, and PCV16-35TT compositions was evaluated by IgG ELISA and a complement-mediated MOPA that measures a functional antibody.

4-1. PCV16-CRM₁₉₇

Serotype Specific IgG Concentration Measurement

Capsular polysaccharides (PnPs) for each serotype were coated on a 96-well plate at 0.5 μg/well to 1 μg/well. An equivalent amount of serum was sampled from each subject and was pooled by group. The serum pool was serially diluted by 2.5 times with an antibody dilution buffer comprising Tween 20 and CWPS 5 μg/mL and then reacted at room temperature for 30 minutes. The plate was washed 5 times with a washing buffer and then pre-adsorbed and diluted serum 50 μl was added to the coated well plate, followed by incubation at room temperature for 2 hours to 18 hours. The well plate was washed in the same way and then goat anti-Rabbit IgG-alkaline phosphatase conjugates were added to each well, followed by incubation at room temperature for 2 hours. Plates were washed as described above and 1 mg/mL p-nitrophenylamine buffer as substrate was added to each well and then reacted at room temperature for 2 hours. The reaction was quenched by adding 50 μl of 3 M NaOH and absorbances at 405 nm and 690 nm were measured. As a comparative example, the commercially available, 13-valent vaccine (PREVNAR13) was subjected to the same procedure. The results are shown in Table 4.

TABLE 4 IgG concentration (U/mL) for 16 serotypes at 3 weeks after secondary immunization PCV16- Serotype PREVNAR13 CRM197  1 320.99 379.99  3 436.85 653.84  4 1820.49 1948.29  5 466.09 380.18  6A 1064.69 1643.6  6B 326.94 552.58  7F 1010.79 833.11  9V 715.40 433.33 12F — 120.44 14 482.05 502.6 18C 1731.07 2915.55 19A 993.68 672.2 19F 863.32 1054.3 22F 1.33 678.45 23F 329.11 185.97 33F 4.58 499.3

PCV16-CRM₁₉₇ was found to lead to good levels of serotype specific IgG concentrations for all 16 serotypes. For PCV16-CRM₁₉₇, the serotypes common to the PCV16-CRM₁₉₇ and PREVNAR13 showed serotype-specific IgG concentrations equivalent to or higher than that of PREVNAR13 and each of the newly added serotypes 12F, 22F, and 33F also showed a good level of serotype specific IgG concentration.

Functional Immunogenicity Test (MOPA)

Antibody functions were evaluated by testing serum in a MOPA assay. S. pneumoniae MOPA strain stored at −70° C. or lower was diluted to the corresponding final dilution fold so that a concentration of each strain was about 50,000 CFU/mL. An equivalent amount of serum was sampled from each subject, pooled by group and 2-fold serially diluted so that 20 μl of serum remained in a U-bottom plate. After diluting the sample, 10 μl of the strain prepared for each serotype was mixed with the diluted sample, and the mixture was allowed to react at room temperature for 30 minutes so that S. pneumoniae and the antibody were well mixed. A mixture of pre-differentiated HL-60 cells and complement was added and reacted in a CO₂ incubator (37° C.) for 45 minutes. The temperature was reduced to stop phagocytosis and 10 μl of the reaction solution was spotted onto an agar plate pre-dried for 30 to 60 minutes, and then allowed to be absorbed onto the plate for 20 minutes until drying. A 25 mg/mL TTC stock solution was added to a prepared overlay agar, and an antibody appropriate for the corresponding strain was added thereto. The mixture was thoroughly mixed, and then about 25 mL of the mixture was added onto the plate and hardened for about 30 minutes. The completely hardened plate was incubated in a CO₂ incubator (37° C.) for 12 to 18 hours and then colonies were counted. MOPA titer was expressed as a dilution rate at which 50% killings were observed. As a comparative example, the commercially-available, 13-valent vaccine (PREVNAR13) was subjected to the same procedure. The results are shown in Table 5.

TABLE 5 MOPA titers for 16 serotypes at 3 weeks after secondary immunization PCV16- Serotype PREVNAR13 CRM197  1 128 128  3 512 1024  4 2048 2048  5 512 256  6A 4096 4096  6B 4096 4096  7F 2048 1024  9V 1024 512 12F 4 1024 14 2048 1024 18C 1024 2048 19A 4096 2048 19F 2048 2048 22F 16 4096 23F 2048 1024 33F 32 1024

All serotypes showed an excellent level of functional immunogenicity in PCV16-CRM₁₉₇. For PCV16-CRM₁₉₇, the serotypes common to the PCV16-CRM₁₉₇ and PREVNAR13 showed functional immunogenicity equivalent to or better than that of PREVNAR13 and each of the newly added serotypes 12F, 22F, and 33F also showed a high level of functional immunogenicity.

4-2. PCV16-13TT

The serotype specific IgG concentration and functional immunogenicity titer were measured in the same manner as in 4-1, except that PCV16-13TT was used instead of PCV16-CRM197, and the results are shown as follows.

Serotype Specific IgG Concentration Measurement

TABLE 6 IgG concentration (U/mL) for 16 serotypes at 3 weeks after secondary immunization PCV16- Serotype PREVNAR13 13TT  1 276.92 844.48  3 539.40 2980.73  4 1000.76 1698.00  5 303.20 184.49  6A 533.35 532.02  6B 172.75 451.18  7F 726.27 3449.73  9V 647.71 725.14 12F 0.37 354.00 14 254.59 582.61 18C 3266.87 5553.58 19A 681.62 1702.05 19F 528.77 1998.83 22F 0.74 1583.58 23F 576.63 367.71 33F 0.25 977.02

When the capsular polysaccharides of serotypes 1 and 3 were conjugated to TT, they showed significantly increased levels of serotype specific IgG compared to that obtained when the serotypes were conjugated to CRM₁₉₇. Also, each of the capsular polysaccharides of serotypes 12F, 22F, and 33F conjugated to CRM₁₉₇ showed a decent level of serotype specific IgG concentration and serotypes 4, 6B, 7F, 14, 18C, 19A, and 19F showed higher levels of serotype specific IgG concentrations than in PREVNAR13.

Functional Immunogenicity Test (MOPA)

TABLE 7 MOPA titers for 16 serotypes at 3 weeks after secondary immunization PCV16- Serotype PREVNAR13 13TT  1 102 645  3 813 3251  4 2580 3251  5 813 406  6A 4096 4096  6B 4096 6502  7F 2580 6502  9V 2048 3251 12F 4 1625 14 2048 4096 18C 4096 4096 19A 2580 5161 19F 2048 5161 22F 8 5161 23F 4096 3251 33F 4 3251

When the capsular polysaccharides of serotypes 1 and 3 were conjugated to TT, the functional immunogenicity improved compared to that obtained when they were conjugated to CRM₁₉₇. Also, each of the capsular polysaccharides of serotypes 12F, 22F, and 33F conjugated to CRM₁₉₇ showed excellent functional immunogenicity and each of the capsular polysaccharides of serotypes 4, 6B, 7F, 9V, 14, 19A, and 19F showed better functional immunogenicity than in PREVNAR13.

4-3. PCV16-15TT

The serotype specific IgG concentration and functional immunogenicity titer were measured in the same manner as in 4-1, except that PCV16-15TT was used instead of PCV16-CRM197, and the results are shown as follows.

Serotype Specific IgG Concentration Measurement

TABLE 8 IgG concentration (U/mL) for 16 serotypes at 3 weeks after secondary immunization PCV16- Serotype PREVNAR13 15TT  1 276.92 1083.23  3 539.40 901.37  4 1000.76 2655.28  5 303.20 2645.56  6A 533.35 1460.65  6B 172.75 603.87  7F 726.27 2285.92  9V 647.71 663.37 12F 0.37 303.99 14 254.59 493.06 18C 3266.87 4075.62 19A 681.62 937.41 19F 528.77 1355.08 22F 0.74 1874.55 23F 576.63 607.40 33F 0.25 880.54

When the capsular polysaccharides of serotypes 1 and 5 were conjugated to TT, the serotype specific IgG concentration significantly increased compared to that obtained when they were conjugated to CRM₁₉₇. Also, each of the capsular polysaccharides of serotypes 12F, 22F, and 33F conjugated to CRM₁₉₇ showed a high level of serotype specific IgG concentration and each of the capsular polysaccharides of serotypes 3, 4, 6A, 6B, 7F, 14, 18C, 19A, and 19F showed a higher level of serotype specific IgG concentration than in PREVNAR13.

Functional Immunogenicity Test (MOPA)

TABLE 9 MOPA titers for 16 serotypes at 3 weeks after secondary immunization PCV16- Serotype PREVNAR13 15TT  1 102 645  3 813 1290  4 2580 4096  5 813 4096  6A 4096 6502  6B 4096 6502  7F 2580 4096  9V 2048 1290 12F 4 1290 14 2048 2580 18C 4096 3251 19A 2580 2580 19F 2048 4096 22F 8 6502 23F 4096 3251 33F 4 2580

When the capsular polysaccharides of serotypes 1 and 5 were conjugated to TT, the functional immunogenicity improved compared to that obtained when they were conjugated to CRM₁₉₇. Also, each of the capsular polysaccharides of serotypes 12F, 22F, and 33F conjugated to CRM₁₉₇ showed excellent functional immunogenicity and each of the capsular polysaccharides of serotypes 3, 4, 6A, 6B, 7F, and 19F showed a higher level of functional immunogenicity than in PREVNAR13.

4-4. PCV16-35TT

The serotype specific IgG concentration and functional immunogenicity titer were measured in the same manner as in 4-1, except that PCV16-35TT was used instead of PCV16-CRM197, and the results are shown as follows.

Serotype Specific IgG Concentration Measurement

TABLE 10 IgG concentration (U/mL) for 16 serotypes at 3 weeks after secondary immunization PCV16- Serotype PREVNAR13 35TT  1 242.33 367.13  3 656.91 1837.36  4 1305.61 1786.84  5 408.78 1316.12  6A 737.55 957.85  6B 167.41 322.61  7F 808.75 1357.46  9V 775.28 966.22 12F 0.25 334.45 14 320.12 1055.422 18C 2920.75 3665.59 19A 652.67 409.17 19F 411.07 534.19 22F 1.15 1176.6 23F 742.55 408.88 33F 0.25 855.55

When the capsular polysaccharides of serotypes 3 and 5 were conjugated to TT, the serotype specific IgG concentration significantly increased compared to that obtained when they were conjugated to CRM₁₉₇. Also, each of the capsular polysaccharides of the serotypes 12F, 22F, and 33F conjugated to CRM₁₉₇ had good serotype IgG concentration and each of the capsular polysaccharides of serotypes 1, 4, 6A, 6B, 7F, 9V, 14, 18C, and 19F showed a higher level of serum specific IgG concentration than in PREVNAR13.

Functional Immunogenicity Test (MOPA)

TABLE 11 MOPA titers for 16 serotypes at 3 weeks after secondary immunization PCV16- Serotype PREVNAR13 35TT  1 128 256  3 512 2048  4 2048 4096  5 512 2048  6A 4096 4096  6B 4096 4096  7F 2048 2048  9V 1024 2048 12F 4 512 14 2048 4096 18C 1024 4096 19A 4096 4096 19F 2048 4096 22F 16 4096 23F 2048 2048 33F 32 2048

When the serotypes 3 and 5 were conjugated to TT, the functional immunogenicity improved compared to that obtained when they were conjugated to CRM₁₉₇. Also, each of the capsular polysaccharides of serotypes 12F, 22F, and 33F conjugated to CRM₁₉₇ showed excellent functional immunogenicity and each of the capsular polysaccharides of serotypes 1, 4, 9V, 12F, 14, 18C, and 19F showed a higher level of functional immunogenicity than in PREVNAR13.

These results show that mixed carrier, 16-valent pneumococcal capsular polysaccharide conjugate compositions induce immunogenicity equivalent to or better than the single carrier, pneumococcal capsular polysaccharide conjugate vaccine, PREVNAR13. They also unexpectedly show that the antibody response to serotypes 1, 3, and/or 5 conjugated to tetanus toxoid in the mixed carrier compositions were significantly enhanced as compared to the antibody responses against the same serotypes conjugated to CRM₁₉₇ in the single carrier PREVNAR 13 vaccine. In addition, they show that the mixed carrier, 16-valent pneumococcal capsular polysaccharide conjugate compositions successfully induce antibody responses against the added serotypes, 12F, 22F, and 33F, providing broader serotype protection than the pneumococcal capsular polysaccharide conjugate vaccines currently on the market.

While one or more exemplary embodiments have been described in the specification, it will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the inventive concept as defined by the following claims.

REFERENCES

The following references are cited in the application and provide general information regarding the technical field and provide assays and other details discussed in the application. The following references are incorporated herein by reference in their entirety.

-   [1] Prymula et al., Lancet, 367:740-48 (2006). -   [2] Vesikari et al., PIDJ, 28(4):S66-76 (2009). -   [3] Dagan et al. Infection & Immunity, 5383-91 (2004). -   [4] Juergens et al., Clinical and Vaccine Immunology,     21(9):1277-1281 (2014). -   [5] Andrews et al., Lancet, 14:839-846 (2014). -   [6] Nurkka et al., Vaccine, 20:194-201 (2001). -   [7] Levin and Stone, J. Immunology, 67:235-242 (1951). -   [8] W.H.O. Manual for the Production and Control of Vaccines:     Tetanus Toxoid, 1977 (BLG/UNDP/77.2 Rev.I) -   [9] Didierlaurent et al., J. Immunol., 183: 6186-6197 (2009). 

What is claimed is:
 1. A mixed carrier, multivalent pneumococcal conjugate composition, comprising 16 different pneumococcal capsular polysaccharide-protein conjugates, wherein each pneumococcal capsular polysaccharide-protein conjugate comprises a protein carrier conjugated to a capsular polysaccharide from a different serotype of Streptococcus pneumoniae, wherein the Streptococcus pneumoniae serotypes are 1, 3, 4, 5, 6A, 6B, 7F, 9V, 12F, 14, 18C, 19A, 19F, 22F, 23F, and 33F, wherein the protein carrier is CRM₁₉₇ or tetanus toxoid, wherein two of the capsular polysaccharides are conjugated to tetanus toxoid and the remaining capsular polysaccharides are conjugated to CRM₁₉₇, and wherein the two capsular polysaccharides that are conjugated to tetanus toxoid are selected from the group consisting of serotypes 1, 3, and
 5. 2. The mixed carrier, multivalent pneumococcal conjugate composition of claim 1, wherein the capsular polysaccharides from serotypes 1 and 5 are conjugated to tetanus toxoid, and the capsular polysaccharides from serotypes 3, 4, 6A, 6B, 7F, 9V, 12F, 14, 18C, 19A, 19F, 22F, 23F, and 33F are conjugated to CRM₁₉₇.
 3. The mixed carrier, multivalent pneumococcal conjugate composition of claim 1, wherein the capsular polysaccharides from serotypes 1 and 3 are conjugated to tetanus toxoid, and the capsular polysaccharides from serotypes 4, 5, 6A, 6B, 7F, 9V, 12F, 14, 18C, 19A, 19F, 22F, 23F, and 33F are conjugated to CRM₁₉₇.
 4. The mixed carrier, multivalent pneumococcal conjugate composition of claim 1, wherein the capsular polysaccharides from serotypes 3 and 5 are conjugated to tetanus toxoid, and the capsular polysaccharides from serotypes 1, 4, 6A, 6B, 7F, 9V, 12F, 14, 18C, 19A, 19F, 22F, 23F, and 33F are conjugated to CRM₁₉₇.
 5. The mixed carrier, multivalent pneumococcal conjugate composition of claim 1, further comprising an adjuvant.
 6. The mixed carrier, multivalent pneumococcal conjugate composition of claim 5, wherein the adjuvant is an aluminum-based adjuvant.
 7. The mixed carrier, multivalent pneumococcal conjugate composition of claim 6, wherein the adjuvant is selected from the group consisting of aluminum phosphate, aluminum sulfate, and aluminum hydroxide.
 8. The mixed carrier, multivalent pneumococcal conjugate composition of claim 7, wherein the adjuvant is aluminum phosphate.
 9. A vaccine comprising the mixed carrier, multivalent pneumococcal conjugate composition of claim 1 and a pharmaceutically acceptable excipient.
 10. A method for prophylaxis of Streptococcus pneumoniae infection or disease in a subject, the method comprising administering a prophylactically effective amount of the mixed carrier, multivalent pneumococcal conjugate composition of claim 1 to the subject.
 11. The method of claim 10, wherein the subject is a human who is at least 50 years old and the disease is pneumonia or invasive pneumococcal disease (IPD).
 12. The method of claim 10, wherein the subject is a human who is at least 6 weeks old and the disease is pneumonia, invasive pneumococcal disease (IPD), or acute otitis media (AOM).
 13. The method of claim 12, wherein the subject is 6 weeks to 5 years of age, 2 to 15 months of age, or 6 to 17 years of age.
 14. The method of claim 10, wherein the subject is a human.
 15. The method of claim 10, wherein the mixed carrier, multivalent pneumococcal conjugate composition is administered by intramuscular injection.
 16. The method of claim 10, wherein the mixed carrier, multivalent pneumococcal conjugate composition is administered as part of an immunization series.
 17. A method for prophylaxis of Streptococcus pneumoniae infection or disease in a subject, the method comprising administering the vaccine of claim 9 to the subject. 